Mitral Stenosis
Title
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Mitral Stenosis
Definition
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Narrowing of the mitral valve
Pathogenesis
Causes
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Rheumatic carditis
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Congenital:
Rare
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Systemic lupus erythematosus:
Following Libmann Sachs endocarditis
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Calcification
Pathophysiology
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Mitral valve orifice narrowed
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Left atrial pressure increases
to ensure left ventricular filling and maintain cardiac output
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Left atrial hypertrophy and
dilatation occur
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Left atrial dilatation will lead
to atrial fibrillation
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As a consequence of the
increased pressure in the left atrium, pulmonary venous pressure increases
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Increase in pulmonary capillary
pressure will lead to pulmonary oedema
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As a compensation for this, the
pulmonary capillaries and alveoli will thicken and pulmonary arterial
vasoconstriction will occur
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This will result in pulmonary
hypertension
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Pulmonary hypertension may lead
to dilatation of the pulmonary artery and result in pulmonary regurgitation
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Pulmonary hypertension also
leads to right ventricular:
Hypertrophy
Failure
Dilatation
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Dilatation of the right
ventricle will cause tricuspid regurgitation
Clinical Features
History
CVS
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Dyspnoea
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Weakness
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Fatigue
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Abdominal swelling
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Swelling of lower limbs
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Palpitations
RS
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Cough:
Blood stained,
frothy sputum
CNS
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Hoarse voice:
Enlarged left
atrium causing recurrent laryngeal palsy
Examination
IS
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Malar flush:
Mitral stenosis with pulmonary hypertension
CVS
Pulse
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Small volume pulse:
Low output
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Sinus rhythm:
Initially
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Atrial fibrillation:
Later, due to left atrial dilatation
JVP
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Elevated:
Right heart failure
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V wave:
Tricuspid regurgitation
Apex
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Tapping apex:
Loud 1st heart sound
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Left parasternal heave:
Right ventricular hypertrophy
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Mid-diastolic thrill
Auscultation
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Loud first heart sound
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Opening snap
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Mid diastolic rumble:
Best heard at the apex or just medial to the
apex
Increases in expiration
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Pre-systolic accentuation
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Loud P2:
Pulmonary hypertension
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Early diastolic murmur:
·
Graham-Steele murmur:
Pulmonary incompetence as a consequence of
pulmonary hypertension in mitral stenosis
RS
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Bilateral basal crepitations:
Left heart failure
GIT
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Hepatomegaly:
Right ventricular failure
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Pulsatile hepatomegaly:
Tricuspid
regurgitation
CNS
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Embolic stroke:
Complicating atrial fibrillation
Investigations
Imaging
Chest X-ray
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Small heart
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Dilated left atrium
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Pulmonary venous hypertension
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Straight left border of heart
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Calcified mitral valve
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Pulmonary oedema
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Kerley B lines
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Pulmonary haemosiderosis:
Mottling
Echocardiogram
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Measures mitral valve area
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Left atrial size
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Right ventricular size
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Function
Cardiac
Catheterisation
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If co-existent cardiac disease is
suspected
Electrophysiology
ECG
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Bifid P wave:
P mitrale
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Right ventricular hypertrophy
Management
Control
Drugs
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Diuretics:
Fluid overload, heart failure
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Digoxin:
Rate control in atrial fibrillation
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Beta-blocker:
To prolong diastole when unfit for operation
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Anticoagulation:
Prevent embolic phenomena
Surgery
Indications for
surgery
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Significant stenosis
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Severe symptoms
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Haemoptysis
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Pulmonary hypertension
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Recurrent thromboembolism despite
anticoagulation
Techniques
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Percutaneous mitral commissurotomy (PMC):
Most symptomatic patients with favourable
mitral valve anatomy
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Closed valvotomy
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Open valvotomy
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Mitral valve replacement
Contraindications to
PMC
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Mitral valve area
>
1.5 cms2
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Left atrial thrombus
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More than mild mitral regurgitation
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Severe or bicommissural calcification
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Concomitant severe aortic valve disease
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Concomitant severe combined tricuspid
stenosis and regurgitation
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Concomitant coronary artery disease
requiring bypass surgery
Prevention
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Antibiotic prophylaxis of rheumatic
fever
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Prophylaxis against infective
endocarditis
